School Choir Moves Cancer-Stricken Teacher To Tears With A Breathtaking Surprise

The tears are instantaneous.

Meet PS22 Chorus, the celebrated elementary school choir in Staten Island, N.Y.

The group is a YouTube sensation. The kids have performed with the likes of Katy Perry and Stevie Nicks of Fleetwood Mac, and had the honor of closing the Oscars with a breathtaking performance of "Over the Rainbow."

So they're somewhat of a big deal. But this could be their most powerful performance yet.

At the end of each year, the group performs a special song, led by director Gregg Breinberg. This year, they dedicated their special song to Adriana Lopez, a PS22 teacher who was recently diagnosed with breast cancer.

The group sang a gripping rendition of Martina McBride's "I'm Gonna Love You Through It" as a "dedication to this strong and inspiring woman," according to the video's description on YouTube.

Ms. Lopez was moved to tears by the children.

And she vowed to fight on.

Get your tissues ready — here is PS22 Chorus' touching performance: